Acute anterior uveitis (AAU), the most common form of intraocular inflammation in man, is an autoimmune disease of the eye. Experimental autoimmune anterior uveitis (EAAU) is a rodent model of AAU. It is produced in the Lewis rat by sensitization to melanin associated antigen (MAA) derived from bovine iris and ciliary body and is mediated by CD4+ T cells. The behavior and function of immune cells in vivo has been hampered by reliance on in vitro tissue culture systems, histologic analysis of tissues or the analysis of cell/factors from sacrificed animals. Recent advances in in vivo imaging techniques has allowed the development of scaled down positron emission tomography (PET) instrumentation with high-resolution and signal sensitivity for application in small animal model. We propose to combine our expertise in PET scanning and the production of positron emitting nucleotides in the Department of Radiology with our expertise in immunology in the Department of Ophthalmology and Visual Sciences to study the immunopathogenesis of EAAU. The specific aims of this proposal are: 1. Design, synthesis and evaluation of relevant pharmaceutical tools. 2. Effect of radionuclide labeled antibodies on immune cell function and binding of the antibodies to their target antigens. 3. Immune cell migration and localization in EAAU.